Cosmic rays alter chemistry of lunar ice

Posted by Emma Woollacott

A bombardment of cosmic rays on the moon's surface could be creating  complex carbon chains similar to those that form the foundations of biological life.

According to scientists from the University of New Hampshire, galactic cosmic rays (CGRs) are releasing oxygen atoms from water ice, which are then free to bind with carbon to form large, 'prebiotic' organic molecules.

In addition, says the team, the radiation process causes the lunar soil, or regolith, to darken over time.

By chance, the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) team was able to make measurements during a period when cosmic ray fluxes were at the highest levels ever observed, thanks to the sun's abnormally extended quiet cycle.

"This has provided us with a unique opportunity because we've never made these types of measurements before over an extended period of time, which means we've never been able to validate our models," says Nathan Schwadron, an associate professor of physics at UNH.

"Now we can put this whole modeling field on more solid footing and project GCR dose rates from the present period back through time when different interplanetary conditions prevailed."

The team believes that cosmic radiation may have been a fundamental agent of change on celestial bodies by irradiating water ice and causing chemical alterations.

Now, however, such radiation presents a hazard for astronauts, and the new observations could help minimize the risk.

"Our validated models will be able to answer the question of how hazardous the space environment is and could be during these high-energy radiation events, and the ability to do this is absolutely necessary for any manned space exploration beyond low-Earth orbit," says Schwadron.